Pupfish

by Aaron Reistad

(Cyprinodon macularius) – Quitobaquito, an oasis in southwest Organ Pipe Cactus National Monument, is home to a peculiar species of pupfish, which found this home when the Sonoyta River meandered south.[1] Once widespread throughout the West, pupfish are now restricted to small pockets in their former regions, usually above sea level.[2] The desert pupfish has lived in the Southwest for around 1.6 million years in a range which includes the San Pedro, Santa Cruz, Gila, Salt, and Colorado Rivers and their tributaries in Arizona and California.[3]

Throughout the course of time as the climate of the Earth become warmer, the pupfish got stranded in shallow pools, where the fish physically adapted into its modern form. Here they are able to reside in water hotter than a hundred degrees and three times saltier than the ocean. Measuring around two inches in length, the fish feeds on plants, insect larvae, water mites, and even its own eggs. In summer the males turn indigo with bright yellow fins like tropical fish.[4] Females and juveniles are silver sided with tan or olive on their backs, and their rounded bodies sport narrow, dark sidebars. Like other fish, pupfish hatch from eggs shortly after deposition and may live as long as three years, but most survive only a year.[5] Pupfish prefer shallow water and can also tolerate high salinity, temperatures, and low amounts of dissolved oxygen. Pupfish can survive in water up to 111 degrees Fahrenheit and as low as 45 degrees.”[6] Pupfish become dormant during the winter, and burrow in the muddy floor of their habitat.[7]

In 1986, the Quitobaquito pupfish made the endangered species list. The only healthy populations of desert pupfish in the Sonoran Desert survive in Quitobaquito Springs and the Cienega Santa Clara in Mexico.[8] Today, an estimated four to five thousand pupfish survive in Quitobaquito Springs in Organ Pipe National Monument. Some of the greatest threats to the pupfish, similar to other fish species are, clogging of the stream channel which provides the water to the home of the pupfish, herbicide and pesticide drift across the border into Organ Pipe from nearby Sonoyta, and trash dumping along Mexican Highway 2, which runs just south of the pond.[9] In 1969 the pupfish were removed from Quitobaquito Springs when the National Park Service was forced to drain the pond after discovering that a nonnative species of fish called Gold Shiners who prey on the pupfish had been released into its waters.[10] The pupfish was later reintroduced and remains to this day.